Scott Teaches Wes Svelte and Sapper

In this episode of Syntax, Scott teaches Wes about Svelte and Sapper — general premise, best practices, and more!

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Show Notes

03:14 - General premise

• Sapper compiles away, removing framework code from build
• Component & Props based
• Easy reactivity
• Built-in tools like animation
• Template-based

07:57 - Svelte 101

• .svelte files
• Files can include <script>, <style>, and straight-up CSS
• Variables are used in templates via {var} - <img {src} /> even works
• Import component and use just like React and Vue

10:49 - Stylin'

• All styles are scoped by default
• global() to wrap around global declarations
• Language type sass to use sass

12:22 - Reactivity

• Baked in
  • let count = 0
  • count = count + 1 will reactively update in template
  • variables are essentially state
  • $: double = count + 2 - to create a reactive variable that updates when another variable updates
  • $: console.log(count) = will run whenever count is update a-la useEffect
  • $: if (count >10) = same... reactive if
  • <input bind:value={name} > updates let name in script

15:55 - Props

• Same was React, but need to be exported before they can be used
• Seems counterintuitive, but you get over it quickly
• EZ defaults export let answer = 'a mystery';

<script>
import Nested from './Nested.svelte';
</script>

<Nested answer={42}/>

<script>
	export let answer = 'a mystery';
</script>

<p>The answer is {answer}</p>

20:08 - Template logic

• If statements {#if user._id} {/if}

• Loops {#each cats as kittens}

• Promise tags

{#await promise}
	<p>...waiting</p>
{:then number}
	<p>The number is {number}</p>
{:catch error}
	<p style="color: red">{error.message}</p>
{/await}

23:12 - Events

• <button on:click={func} />
• On directive
• Functions can also be inline
• Modifiers

<button on:click|preventDefault={handleClick}>
	Click me
</button>

26:11 - Baked-in goodies

• Animation
• Dimensions

<div bind:clientWidth={w} bind:clientHeight={h}><span style="font-size: {size}px">{text}</span></div>

• Lifecycle methods
• Advanced State Via Stores
  • A store is simply an object with a subscribe method that allows interested parties to be notified whenever the store value changes.
• import { writable } from 'svelte/store';
• export const count = writable(0);
• count.update(0)
• Slots
• React helmet like stuff, ie svelte:head

36:39 - Sapper

• Similar to Next.js
• Folder routes
• Static export with all of the good stuff like service workers and preloading

Links

• Svelte
• Sapper
• r/webdev
• Vue.js
• ScottTolinski.com
• WesBos.com
• Next.js
• ScottTolinski.com Github Repo
• Gatsby.js
• Shawn Swyx

××× SIIIIICK ××× PIIIICKS ×××

• Scott: Lewisia Battery Backup Solar Fountain Pump
• Wes: Firefox Containers

Shameless Plugs

• Scott: LevelUpTuts YouTube Channel
• Wes: Wes' New Website

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